Description

In preparation for
AO3-4716
Deployed
, the existing admin user views and tests need updating to our current code standards. This is being done as part of a separate ticket to make the one that adds new functionality easier to review. It will also add some tests to improve coverage (if required)

Testing
If the automated tests run smoothly, this should just need a smoke test - check that the admin users page looks the same as before, and that you can search and administer users as expected.